Condenser neck between a steam turbine and a condenser

ABSTRACT

A condenser neck ( 1 ) comprises two level cover plates ( 2 ) and two side walls ( 3 ) located between them that are favorably shaped with respect to flow technology. The cover plates ( 2 ) and side walls ( 3 ) may be reinforced with ribs ( 4   a   ,4   b ). A pipe ( 5 ) arranged between the cover plates ( 2 ) further reinforces the condenser neck ( 1 ). It would also be conceivable to provide openings ( 11 ) for bypass lines in the pipe ( 5 ) and/or in the side walls ( 3 ).

[0001] This application claims priority under 35 U.S.C. §§119 and/or 365to Appln. No. 100 33 691.4 filed in Germany on Jul. 11, 2000, the entirecontent of which is hereby incorporated by reference.

FIELD OF THE INVENTION

[0002] The invention relates to a condenser neck provided between asteam turbine and a condenser located downstream from the steam turbine.

BACKGROUND OF THE INVENTION

[0003] EP-A1-384 200 discloses an arrangement of a steam turbine andsubsequent steam condenser. A coupling pipe and a condenser neck arelocated between the two elements that are located in one plane. Thesteam from the steam turbine is fed via the coupling pipe and condenserneck to the pipe bundle of the condenser. This condenser neckessentially has the task of providing a homogeneous flow field and aclean steam-flushing of the subsequent bundles of the condenser. Thecondenser neck of this steam condenser widens in a cone shape from thecoupling pipe to the condenser.

[0004] Another embodiment of such a condenser neck is known from U.S.Pat. No. 2,939,685.

[0005] Also known are condenser necks that are comprised of levelplates. Since very high vacuum forces act on the condenser neck, it isreinforced on the inside with pipes. Now and then, additional ribs areprovided on the outside. These pipes are necessary, but significantlyinterfere with the flow of the steam. On the side of the pipes thatfaces away from the flow, oscillating vortices that are not veryadvantageous form and excite the support pipes and therefore the entirecondenser neck. The result can be a failure of the reinforcement pipes,even a total failure of the system and damage of all involvedcomponents. During bypass operation, i.e., when hot steam is introduceddirectly into the condenser neck while bypassing the turbine, whichoccurs, for example, during a sudden shut-down of the turbine, there areoverall difficulties in introducing the steam. There is a danger oferosion of the support pipes and walls. The large number of pipes usedrequires a complex assembly of the plates, pipes, and ribs with welding.Because it uses level plates, this type of condenser neck also has ashape with little advantages with respect to flow technology.

SUMMARY OF THE INVENTION

[0006] It is the objective of the invention to avoid the mentioneddisadvantages. The invention solves the task of constructing a condenserneck with increased stability in relationship to external influences,whereby the flow of the steam is influenced or impaired as little aspossible.

[0007] According to the invention, this is achieved by a condenser neckhaving two level cover plates and two side walls that widen in the flowdirection of the steam and have a favorable shape with respect to flowtechnology.

[0008] This simple construction makes it possible that the forces actingon the condenser neck are absorbed in an improved manner. This is truein particular if the cover walls and/or side walls are reinforced withribs. A pipe arranged between the cover walls is able to additionallysupport this reinforcement. The flow inside the condenser neck improvesboth because of the favorable shape as well as because previously knowninternal elements are eliminated. The existing pipe is preferablyarranged so that it is located in a zone with little flow, so that thesteam flow is influenced as little as possible. Any existing bypasslines may merge into the pipe as well as into the side and/or coverwalls. If a compensator is provided between the turbine and thecondenser, two connecting surfaces or connecting tabs are provided onthe coupling pipe on the turbine side at the inlet opening; in this waythe external loads are transmitted from the turbine side via astabilized element onto the condenser casing. In an embodiment withoutcompensator, the coupling pipe of the turbine is welded to the neck. Theforce in the condenser neck according to the invention is distributedevenly over its circumference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A preferred embodiment of the condenser neck according to theinvention is described with reference to the accompanying drawings, inwhich:

[0010]FIG. 1 is a perspective view of a condenser neck according to theinvention;

[0011]FIG. 2 is a top plan of the condenser neck according to theinvention;

[0012]FIG. 3 is a side elevational view of the condenser neck accordingto the invention; and,

[0013]FIG. 4 is a cross-sectional view along the line IV-IV in FIG. 3with openings for a bypass line.

[0014] Only those elements essential for the invention are shown.Identical elements are identified with the same reference numbers indifferent drawings. The flow directions are indicated by arrows.

DETAILED DESCRIPTION OF THE INVENTION

[0015]FIG. 1 shows a perspective view of a condenser neck according tothe invention that is located between a steam turbine (not shown) and acondenser (also not shown). The principal arrangement of these elementsis known from document EP-A1-384 200 (FIG. 1). The condenser neck 1according to the invention of FIG. 1 comprises two level cover plates 2and two side walls 3 located between the cover plates 2. The side walls3 widen between an inlet opening 9 an outlet opening 10 of the condenserneck 1 in a shape that is favorable with respect to flow technology, forexample, as shown in FIG. 1, in the form of a nozzle, diffuser orsimilar form. The steam 6 flows in the direction of the arrow from theinlet opening 9 to the outlet opening 10.

[0016] Both the cover plates 2 and the side walls 3 are reinforced withribs 4 a, 4 b. In addition, a vertical pipe 5 is provided centeredbetween the cover plates 2 in the condenser neck 1, which also functionsas a reinforcement of the condenser neck 1. The pipe 5 is providedapproximately in the last third towards the outlet opening 10 of thecondenser neck 1. This means that the pipe 5 is installed at a point atwhich it has only a slight influence on the steam flow. At the coverplates 2, the ribs 4 a are arranged in a star shape around the pipe 5.The horizontal ribs 4 b of the side walls 3 are oriented approximatelyparallel to the (main) flow direction of the steam 6. The vertical ribs4 b are perpendicular to the horizontal ribs 4 b. Naturally, the numberof shown ribs 4 a, 4 b is used only as an example. They may vary inrelation to the specific design (size, specifications for stability,etc.) of the condenser neck 1. The horizontal ribs 4 b in this case havea reinforcing effect. The side walls 3 have been installed so that onthe inlet opening 9 one each connecting surface 7 is created on theside. These connecting surfaces 7 are used for attachment on the turbineside, and therefore also for absorbing external loads. Forces from theturbine side due to vacuum, ground vibration, piping, or other causesare transmitted via the connecting surface 7 and are absorbed, inparticular, by the reinforced side walls 3 or cover plates 2 and thentransmitted to the condenser casing (not shown). In the condenser neck 1according to the invention, the applied force in this manner isdistributed evenly over the circumference. The condenser neck 1 can beused in connection with an axial or lateral arrangement of the steamturbine and condenser.

[0017]FIG. 2 and 3 show two more views of the condenser neck 1. FIG. 2,which is a view from the top, clearly shows the star-shaped arrangementof the ribs 4 a on the condenser neck 1 around the pipe 5, and the shapeof the side walls 3 that is favorable with respect to the flow. FIG. 3shows a lateral view of the condenser neck 1.

[0018]FIG. 4 shows a section according to line IV-IV in FIG. 3 throughthe condenser neck 1 according to the invention. It is obvious that boththe pipe 5 as well as the side walls 3 and/or cover walls 2 may beprovided with openings 11 connected to a bypass line (not shown). In thecase of a turbine shutdown, these bypass lines feed the steam directlyinto the condenser, bypassing the turbine in the process. Since thenumber of internal elements is clearly reduced in comparison to thestate of the art, the danger of erosion due to the introduced steam isreduced. The centered arrangement of the pipe 5 also reduces the risk ofan erosion of the side walls 3. The arrangement of openings 11 for thebypass lines in the pipe 5 is also advantageous because it provides avery large surface for this purpose.

What is claimed is:
 1. Condenser neck (1) provided between a steamturbine and condenser, used to feed steam from the steam turbine to thecondenser and provided with an inlet opening (9) and an outlet opening(10), characterized in that the condenser neck (1) comprises two levelcover plates (2) and two side walls (3) widening in the flow directionof the steam (6), said side walls being favorably shaped with respect toflow technology.
 2. Condenser neck (1) as claimed in claim 1,characterized in that at least one of the cover plates (2) and/or atleast one of the side walls (3) is reinforced with ribs (4 a, 4 b). 3.Condenser neck (1) as claimed in claim 1 or 2, characterized in that apipe (5) is provided between the cover plates (2).
 4. Condenser neck (1)as claimed in claim 3, if the latter is dependant on claim 2,characterized in that the ribs (4 a) of the at least one cover plate (2)are arranged in star shape around the pipe (5).
 5. Condenser neck (1) asclaimed in claim 3, characterized in that the pipe (5) is arrangedcentered between the cover plates (2) between the side walls (3) in theback third towards the outlet opening (10).
 6. Condenser neck (1) asclaimed in one of claims 1 to 5, characterized in that openings (11),into which a bypass line merges, are provided in at least one coverplate (2) and/or in at least one side wall (3) and/or the pipe (5)located between the cover plates (2).
 7. Condenser neck (1) as claimedin one of claims 1 to 6, characterized in that connecting surfaces (7)are provided at the inlet opening (9), laterally towards the side walls(3).
 8. Condenser neck (1) as claimed in claim 7, characterized in thatthe condenser neck (1) is used with an axial arrangement of steamturbine and condenser.